This is a request for a K05 Senior Scientist Research Career Award (RCA) as a competing continuation of #5 K05 DA00017. The specific aims of the proposed five-year research program are the following: 1. Develop new psychometric methods for drug abuse research; 2. Apply these newly developed methods to important drug abuse data sets; 3. Generate practical improvements in methodology; 4. Create nontechnical papers and tutorials to improve methodology in drug abuse research; and 5. Advise drug abuse and health researchers and government agencies on methodology. The research program is directed towards the development of new multivariate psychometric and statistical techniques that hold special promise for improving the quality of psychosocial, social, behavioral, epidemiological, and functional imaging health-related research on drug use and abuse. Methods for robustly analyzing experimental and nonexperimental drug abuse data that may contain selectivity, outlier cases, arbitrary distributions, errors in measurement, nonstandard sampling plans, small samples, dependent observations, etc. will be developed. Special attention is given to structural equation models that may involve latent variables in mediation and moderator relations. Optimal small sample, missing data, robust, multilevel nonnormal, bootstrap, functional imaging, supercomputer research methods are a special focus. While no data will be gathered under this grant, the newly developed techniques will be extensively evaluated for their practical relevance to drug abuse research by addressing important substantive issues in drug abuse on high-quality data obtained in association with NIDA/UCLA program project grant P01 DA01070, via collaboration with brain mapping researchers and nationally active substance abuse researchers working on their own projects, as well as by cooperation with NIDA and other health-related agencies. Methods that are developed under this grant also will be widely disseminated.